After a text has been retrieved through a text search process, a user must make a further search for retrieving the required text part from the displayed text if the searched text is still so bulky as to contain many topics. In such a case, if the user makes a search through the text segments that have been segmented beforehand based on topics, the user will be able to immediately display the desired text segment. And accordingly it may become unnecessary for the user to make a further search for the required part. Therefore, if the text is segmented based on topics, it will be easy to perform various text processing applications.
Several text segmentation methods are disclosed in, for example, Laid Open Japanese Patent Application No. H11-242684, Laid Open Japanese Patent Application No. 2000-235574 and Laid Open Japanese Patent Application No. H10-72724. Laid Open Japanese Patent Application No. H11-242684 proposes a text segmentation apparatus wherein texts are handled in terms of not only association between adjacent sentences but also global sentence association. Japan Patent Application No. 2000-235574 proposes a method for obtaining segmentation points based on a square matrix whose elements include relativeness between the paragraphs, the text being segmented in accordance with a paragraph format and the like. Laid Open Japanese Patent Application No. H10-72724 proposes a method comprising the steps of determining the relativeness at each position based on a plurality of windows, determining the border of the topics for each layer and integrating those borders to identify the topic border.
It is possible to segment a text in terms of topics using the above-referenced methods. However, those referenced methods do not take into consideration the size of the text. In particular, when using such equipments as mobile telephones and PDA devices that have some limitation on the resources, e.g., small size of the display, users may need an extra operation, for example, a scrolling, to display the segmented text segments. In addition, the size of the text segments may be beyond the limit of the storage of such equipment. Accordingly, the text segment that is segmented by one of the above-referenced conventional text segmentation methods cannot be necessarily a desirable segmentation unit to users and/or terminal devices.
Therefore, there is a need for a text segmentation method for segmenting a text in accordance with coherent units as well as a specified text segment size. Also, there is a need for a technique for providing a group of text segments which users can easily read through even if they are displayed on small size display screens of mobile telephones and/or PDA devices.